/*
 *  Copyright 2008-2010 NVIDIA Corporation
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */


/*! \file distance.h
 *  \brief Dispatch layer to distance function.
 */

#pragma once

#include <iterator>

namespace thrust {

namespace detail {

namespace dispatch {

template<typename InputIterator>
inline typename thrust::iterator_traits<InputIterator>::difference_type
distance(InputIterator first, InputIterator last,
         thrust::single_pass_traversal_tag) {
    typename thrust::iterator_traits<InputIterator>::difference_type result = 0;

    while (first != last) {
        ++first;
        ++result;
    }

    return result;
} // end distance()


template<typename InputIterator>
inline typename thrust::iterator_traits<InputIterator>::difference_type
distance(InputIterator first, InputIterator last,
         thrust::random_access_traversal_tag) {
    return last - first;
} // end distance()

} // end namespace dispatch

} // end namespace detail

} // end namespace thrust

